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What is Botulism? Our Guide to Types, Causes, and Prevention
- Dr Ravi Gowda
- Aug 21
- 5 min read
Updated: Oct 14
With recent outbreaks making headlines, it’s important to separate fact from fear. As an Infectious Diseases Consultant, I’ve seen, at first-hand, the devastating consequences botulism toxicity in my patients.
Here’s what you need to know about botulism:
Botulism has once again entered the news following recent cases in Calabria and Sardinia in Italy, where a number of people were hospitalised and sadly, 4 lives were lost after eating contaminated foods. Although extremely rare, botulism carries a very high risk of severe illness and death if not recognised early. It’s caused by one of the most powerful toxins known to medicine. While outbreaks are more commonly reported in certain regions of the world, botulism remains a risk everywhere, including here in the UK. Understanding how it arises, its symptoms, and how to prevent it is the best way to stay safe.
In this article we’ll run through:
What is Botulism & How is it Transmitted
Botulism is a serious illness caused by botulinum toxin, a poison produced by the bacterium Clostridium botulinum. This bacterium exists widely in the environment as spores—in soil, riverbeds, and even on surfaces of fruit and vegetables. Spores themselves are harmless if ingested, but under the right conditions they germinate and produce toxin.
Clostridium botulinum thrives where oxygen is absent, acidity is low, and temperatures are not high enough to kill spores. This is why improperly canned or bottled foods, vacuum-packed items, and foods preserved in oil are common culprits. If you dabble in preserving foods in such a manner, be really careful. The botulinum toxin blocks signals between nerves and muscles, leading to weakness, paralysis and, in the most severe cases, respiratory failure.
Types of Botulism
Botulism is not a single condition. There are several forms, each linked to a different route of exposure:
Foodborne botulism: In this form you may be affected by eating food containing pre-formed toxin. Home-canned vegetables, fish, and meat products are typical sources. Commercial outbreaks, though less common, have been reported when safety measures failed
Wound botulism: Spores enter a wound, multiply, and produce toxin. This can occur after traumatic injuries or, increasingly, in people who inject drugs using unsterile equipment
Infant botulism: Infants under 12 months are uniquely at risk. Their gut flora (the normal bacteria present in the intestine) is immature, allowing spores to grow and release toxin. Honey is a well-known source, which is why it should never be given to babies
Botulism toxicity from injections: Rare cases have been linked to medical or cosmetic use of botulinum toxin (such as Botox) when unlicensed products or unsafe techniques were used. UKHSA, (UK Health Security Agency) has warned about this risk in recently.
Intestinal botulism in adults: Very rare. Similar to infant botulism, it occurs when spores colonise the gut, usually in people with underlying health conditions.
Symptoms of Botulism
The symptoms of botulism can appear within hours to a few days after exposure. It’s important that you (and doctors) recognise the symptoms early, as this will give you the best chance of survival. If they’re missed, then this can delay in diagnosis increases the risk of severe complications and recovery is less likely.
Here’s what you should look out for:
Difficulty swallowing or speaking
Muscle weakness, starting in the face and descending to the arms, chest, and legs
Double or blurred vision, drooping eyelids
Slurred speech
Difficulty breathing due to weakened chest muscles
Difficulty moving the eyes
Gastrointestinal upset (nausea, vomiting, abdominal cramps) in foodborne botulism
In infants: constipation, poor feeding, weak cry, floppiness, and poor muscle tone
If you don’t remember anything else, botulism is a progressive, symmetrical weakness without fever or loss of consciousness. This is the key bit, you’re conscious and alert but have profound weakness. If untreated, paralysis can progress to the breathing muscles, so you’ll need a ventilator to keep you breathing.
Botulism Prevention
Fortunately, botulism can be prevented through safe practices. If you’re into home canning and food preservation, follow these key rules:
Safe food handling: Always follow tested home-canning guidelines. Low-acid foods such as beans, beetroot, peas, fish, and meat require pressure canning to destroy spores. Boiling water methods are insufficient
Recognising risky food: Never eat from cans or jars that are bulging, leaking, or have an off odour. Although botulinum toxin has no taste or smell, these signs may indicate contamination
Honey and infants: Do not give honey to children under one year old. Even a small amount may contain spores
Safe wound care: Clean wounds thoroughly and seek medical advice if infected. People who inject drugs are at particular risk of wound botulism
Cosmetic injections: Only seek treatments such as Botox from qualified, licensed practitioners using authorised products. Unregulated providers have been linked to serious complications. We’ve had 41 such cases of botulinum toxicity in the UK in just 2 months between June and August 2025.
Botulism Treatment
If you think you’ve got botulism, urgent recognition and treatment in hospital is essential. This is because you’ll need anti-toxin while the botulinum toxin is still in the blood stream and before it attaches to the nerves. The antitoxin binds and neutralises the circulating toxin before it can attach to nerves. However, it cannot undo damage already caused, so time is critical.
Supportive care is equally vital. Many patients require intensive care, with mechanical ventilation to support breathing. Recovery can be slow, taking weeks or months as nerve endings regenerate. With prompt treatment, most people do eventually recover.
In the UK, antitoxin is accessed through national public health services, and doctors are encouraged to seek immediate advice if botulism is suspected. Wound botulism may also require antibiotics and surgical cleaning of the wound.
Botulism FAQs
Can you get botulism from glass jars?
Yes. If food inside has been improperly preserved, spores can survive and produce toxin even in sealed glass jars.
Can dented cans cause botulism?
Yes, especially if the seal has been compromised. Bulging or leaking cans should never be consumed.
Is botulism a bacteria?
Strictly speaking, botulism is the illness caused by the toxin from the bacterium Clostridium botulinum.
What does botulism look like?
Food contaminated with botulinum toxin often looks and smells normal. Warning signs include bulging cans or unusual odours, but absence of these does not guarantee safety.
How common is botulism?
It’s very rare. Fewer than 10 cases are reported each year in the UK (except for Botulinum toxicity associated with Botox treatment), but outbreaks continue to occur worldwide.
Final Thoughts
Botulism is one of the most severe forms of foodborne and wound-related illness, yet it’s also one of the most preventable.
Simple precautions—safe food preparation, avoiding honey in infants, careful wound care, and choosing regulated providers for cosmetic injections—go a long way in reducing risk. Although rare, recognising the symptoms quickly and seeking immediate medical help can be life-saving.
References
1. Centers for Disease Control and Prevention (CDC). Botulism – Overview, Symptoms, Treatment, Prevention. https://www.cdc.gov/botulism/
2. World Health Organization (WHO). Botulism Fact Sheet. https://www.who.int/news-room/fact-sheets/detail/botulism
3. UK Health Security Agency (UKHSA). Guidance and Warnings on Botulism. https://www.gov.uk/
4. NHS. Botulism: Symptoms, Causes, Treatment. https://www.nhs.uk/conditions/botulism/
Written and Approved by:
Dr Ravi Gowda, Consultant Physician in Infectious Diseases and Travel Medicine , MBBS, MRCP(UK), DTM&H, MRCGP, DCH, DRCOG, DFFP